Fluid-pressure impact-tool.



PATENTED JULY 18, 1905.

0. K. PIGKLBS. FLUID PRE SSURE IMPAGT TOOL.

APPLIOATION n LED my 31,1901.

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Inventazu Mwfizv Atieayi;

ha m w w PATENTED JULY 18, 1905.

0. K, PIGKLES. FLUID PRESSURE IMPAGT TOOL.

APPLICATION TILED MAY 31, 1901.

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Milli J m I UNITED STATES Patented. July 18, 1905.

PATENT OFFICE.

CHARLES K. PICKLES, OF ST. LOUIS, MISSOURI, ASSIGNOR TO FAIR- BANKS, MORSE & COMPANY, OF CHICAGO, ILLINOIS, A CORPORA- TION OF ILLINOIS.

FLUID-PRESSURE IMPACT-TOOL.

SPECIFICATION forming part of Letters Patent No. 794,738, dated July 18, 1905.

Application filed May 31, 1901- Serial No. 62,582.

To all whom it may concern:

Be it known that I, OnARLns K. PICKLES, a citizen of the United States of America, residing in the city of St. Louis, State of Missouri, have invented certain new and useful Improvements in Fluid -Pressure Impact-Tools, of which the following, taken in connection with the accompanying drawings, is a specification.

My invention has reference to the provision of improvements in the type of mechanism specified, in which, the piston is driven backward and forward by pressure admitted alternately at its opposite ends through. control exercised by a suitable valve placed in a valve chamber adjacent to the piston chamber and connected therewith by suitable ports and passages, the valve being governed in its movements by suitable ports controlled by the piston.

In order to make my invention clearI have illustrated it in preferred form in the accompanying drawings, in which, Figure 1 is a side sectional view of a tool embodying my improvements, Figure 2 is asectional view of the impact piston, Fig. 3 is a side elevation of the controlling valve, Fig. 4-. is a side elevation of the controlling valve bushing, Fig. 5 is a vertical section showing the parts in a different position from that shown in Fig. 1, Fig. 6, is a section taken on the line 6-6 of Fig. 5, Fig. 7 is a section taken on the line 7 -7 of Fig. 5, Fig. 8 is a section taken on the line 8-8 of Fig. 5, all of the last mentioned th ee figures being designed particularly to show the different connections and port openings involved in the operation of the device.

In constructing a tool in accordance with my invention Iprovide, first, asuitablecylinder 9, carrying in its forward end atool socket or bushing 10, which may be of any preferred construction, so formed as to permit the tool to be held against rotation or to permit the tool to rotate within the bushing as may be desired. At the end of the cylinder 9, opposite the said tool socket, is connected a handle, by means of a handle hub 11 having screw threaded engagements with the exterior of the cylinder 9, and locked in position, after it is convenience shown a well known form in which the throttle is located in the lower portion, and the duct through which thepressure reaches the tool passes through the lower connecting neck between the grasping portion and the hub of the handle. The throttle valve is controlled by means of a trigger lever of the usual type.

Within the cylinderI provide a piston bushing 12 open at its forward end and closed at its rear end by means of a piston chamber cap 14 held in place by a spring in the form of a disk 15 pressing against the rear of the cap and held by means of a portion of the handle hub whereby the closure cap is not only held tightly against the piston bushing butaslight amount of spring is obtained which tends to take up such wear as may occur in the threaded connection between the handle hub and the cylinder on account of the constant vibration and jolt to which the tools are subject in use. The cap 14 is located within a chamber 14: formed in the handle hub so as to permit the air pressure to act against the rear side of the cap as well as the front side and keep the same in equilibrium.

Within the piston bushing is arranged a piston 13 the same being provided with two annular grooves or passages 13 and 13 the latter connected with the forward end of the piston by longitudinal channels 13 and the former with the rear end of the piston by means of a port or opening 13 constructed to be closed by means of a ball check valve 21 for a purpose which will be hereinafter pointed out.

Within the lower part of the handle hub is inserted a valve bushing 17 adapted to receive the controlling valve 16 and closed at its. lower end by means of a chamber cap 18, which is provided with a tubular extension 19 that projects through the valve. The valve bushing is provided with an inlet port 17 and with three exhaust ports the two marked 11 being ports for allowing the pressure to exhaust when the piston is being returned or reset af- 1 fluid pressure in its forward piston chamber ter an impact stroke and the one marked 11 for permitting the exhaust of the pressure in advance of the piston as it is making its impact stroke. The last mentioned port 11 is connected with the forward end of the piston chamber by means of an annular passage 12 formed in the exterior of the piston chamber bushing and three longitudinal passages one on each side and one on the top of the piston bushing which extends to the forward end thereof.

The valve 16 is what is known as a diflerential valve having an enlarged end 20, which works within an enlargement of the valve chamber the lower end being connected by means of a passage 12 formed longitudinally in the lower side of the piston bushing 12, as clearly shown in the drawings. The tubular extension 19 is open at the upper end to the inlet passage so that it is constantly supplied with fluid pressure and has near its lower end a small port 19 controlled by the valve, which when the valve is in upper position permits the air to flow into the passage 12 for resets ting or returning the piston after it has made an impact stroke and also for the purpose of holding the valve in its upper position during the return or resetting stroke of the piston.

The operation of my invention is as follows: Air having been admitted by the opening of the throttle valve the fluid pressure acting on small area moves the valve to the position shown in Fig. 5, whence it passes through the impact ports 17 and the radial ports 12 into the rear end of the piston chamber forcing the piston forward to deliver an impact blow, the piston at the time of striking the tool being in the position shown in Fig. 5 at which time air then enters through the check valve passage 13 and the annular port 13 and passing thence through the valve change port 12 in the piston bushing acts backwardly into the enlarged end of the piston chamber and against the end 20 of the valve to force the valve back to the position shown in Fig. 1. This'opens the resetting port 19 permitting fluid pressure to enter to hold the valve in.

this position, and, at the same time passes to the forward end of the piston chamber to move the piston back, the rear end of the piston chamber being meanwhile in communication with the atmosphere through the ports and passages 12 12 and 11, respectively. As the piston continues its resetting or backward stroke it finally passes the radial ports 12 and then cushions upon the air confined in the rear of the piston chamber, the pressure therein being gradually permitted to escape through the small passage 12 which latter serves the purpose also of admitting the pressure to produce the initial movement of the piston at the beginning of its impact stroke. As the piston reaches the rear end of its stroke it opens communication between the and the atmosphere through the passage 13 and the annular channel 13 whereby the pressure on the large end of the valve is removed and the constant pressure onthe small end thereof causes a change in the valve position shifting it again" to the position shown in Fig. 5.

My invention is applicable to either a long or a short stroke hammer, it being useful for a long stroke hammer without the addition of any auxiliary or secondary valve, the valve mechanism being peculiarly well adapted for such purpose owing to its location at the side of the piston chamber along which it extends longitudinally thus appreciably shortening the length of ports necessary to establish communication between the valve chamber and the forward end of the piston chamber. The use of the check valve carried by the piston is also of peculiar utility in a long stroke hammer.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. The combination with afluid-pressure aotuated impact tool having a cylinder, an impact piston, and a piston chamber, of a valve chamber, ports and passages connecting said piston chamber and said valve chamber, a valve operating in said valve chamber and controlling said ports and passages, and a tubular extension within said valve, substantially as described.

2. The combination with a fluid-pressure actuated impact tool' having a cylinder, an impact piston and a piston chamber, of a valve chamber, ports and passages connecting said piston chamber and said valve chamber, a valve operating in said valve chamber and controlling said ports and passages, and a tubular extension within said valve, said tubular extension being open at one end to constant pressure and provided at the other end with a resetting port, substantially as described.

3. A valve mechanism for fluid-pressure actuated impact tools comprising a valve having differential pressure areas, a chamber within which said valve operates, and a tubular extension within said valve, said tubular extension being provided with a resetting port controlled by the valve, substantially as described.

4. The combination with a pneumatic tool having a cylinder, and impact piston, a piston chamber, and suitable controlling valve mechanism, of a port in said piston for changing the position of said valve, said valve change port being controlled by a check valve, substantially as described.

5. A fluid-pressure impact tool comprising a cylinder, an impact piston, a valve, ports and passages and means carried in said piston whereby a reversal of the valve may be efiected, by fluid pressure from the piston chamber.

6. A fluid-pressure impact tool comprising a cylinder, having ports, and passages, and im pact piston and means carried in said piston whereby a communication may be established between the forward and rear piston chamber to eflect a retraction of the piston, substantially as described.-

7. A fluid-pressure impact tool comprising a cylinder, having ports and passages, and means carried in said piston whereby a communication may be established between the forward piston chamber and the atmosphere to effect a release of motive fluid, substantially as described.

8. A fluid-pressure impact tool comprising a cylinder, having ports and passages in communication with a valve, and a piston having passages adapted to open communication into one side of said valve to eflect a movement in one direction, by the admission of motive fluid from the rear piston chamber, substantially as described.

9. A fluid pressure impact tool comprising a cylinder, having ports and passages, a piston adapted to have movement therein, and having passages whereby, motive fluid is admitted from the rear piston chamber, to move the valve. in one direction,'and means carried by said piston whereby, motive fluid is exhausted from the forward piston chamber, to effect a movement of the valve in the opposite direction, substantially as described.

10. Afluid pressureimpaet tool comprising a cylinder, having ports and passages, a piston adapted to travel therein a greater distance than its own length, and a valve, adapted to control the admission of motive fluid through itself to both ends of said cylinder to effect a movement of the piston, and means carried by the piston for effecting a reversal of the valve.

11. The combination with a pneumatic tool having a cylinder, an impact piston, a piston chamber, and suitable controlling valve mechanism, of a valve port for changing the position of said controlling valve mechanism, said valve change port being provided with a check valve, substantially as described.

12. The combination with a pneumatic .tool having a cylinder, an impact piston, a piston chamber, and suitable controlling valve mechanism comprising a piston having large and small area, of a valve port for changing the position of said controlling valve mechanism, said valve change port being provided with means whereby to prevent reflux of motive fluid from the chamber atone side of the large area of the valve, back into the piston chamber, substantially as described.

13. A fluid pressure impact tool comprising a cylinder having passages and ports, a sepa-,

said rear of the piston.

CHARLES K. PIOKLES.

Witnesses:

PAUL CARPENTER, H W. SMALLEY. 

